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首页> 外文会议>Proceedings of the American Society for Composites Thirtieth technical conference >The Effects of Extrudate Swell, Nozzle Shape, and the Nozzle Convergence Zone on Fiber Orientation in Fused Deposition Modeling Nozzle Flow
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The Effects of Extrudate Swell, Nozzle Shape, and the Nozzle Convergence Zone on Fiber Orientation in Fused Deposition Modeling Nozzle Flow

机译：熔融沉积建模喷嘴流动中挤出物的溶胀，喷嘴形状和喷嘴会聚区对纤维取向的影响

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摘要

Fused Deposition Modeling (FDM) is a rapidly growing Additive Manufacturingrn(AM) technology that allows for low cost and intricate three-dimensional parts to berncreated. FDM parts are created in layers by extruding a bead of polymer melt from arnfilament fed nozzle onto a platform. Several recent developments aimed at improvingrnthe mechanical properties of FDM components have focused on adding structuralrnchopped fibers to the FDM filament feedstock. It is understood that the discrete fibersrnwill orient in response to the melt flow within the nozzle. In addition the fluidrnexpansion effects of extrudate swell at the nozzle exit impacts the melt velocityrngradients and therefore the underlying fiber orientation. The local varying fiberrnorientation directly impacts the mechanical properties of the part, making the fiberrnorientation prediction during processing a necessary portion of FDM composite partrndesign. A computational approach is presented for determining fiber orientation in thernnozzle flow domain taking into consideration the effects of the convergence zone inrnthe FDM extrusion nozzle, the fluid expansion caused by extrudate swell, and nozzlernshape on the fiber orientation in the extruded polymer. The polymer melt is modeledrnas a Newtonian fluid in Creeping flow and includes extrudate swell expansion. Fiberrnorientation is calculated using the Advani-Tucker (1987) orientation tensors with thernFast Exact Closure from Montgomery-Smith, et. al. (2009) assuming the Folgar-rnTucker (1984) isotropic rotary diffusion model for fiber-fiber interactions. The resultsrnshow that the shear flow prior to the nozzle section causes high alignment in therndirection of the flow as is expected. This alignment state is further increased within thernnozzle convergence zone. The expansion flow in the die swell region causes arnnoticeable decrease in fiber alignment in the direction of the flow and an increase inrnfiber alignment transverse to the flow direction.
机译：熔融沉积建模（FDM）是一项快速发展的增材制造（AM）技术，可用于制造低成本和复杂的三维零件。 FDM零件是通过将聚合物熔体的珠子从细丝进料的喷嘴中挤出到平台上而形成的。旨在改善FDM组件的机械性能的一些最新进展集中在向FDM长丝原料中添加结构短切纤维。应当理解，离散的纤维将响应于喷嘴内的熔体流动而取向。另外，挤出物溶胀在喷嘴出口处的流体膨胀作用影响熔体速度梯度并因此影响下面的纤维取向。局部变化的纤维取向直接影响零件的机械性能，使得在加工过程中预测纤维取向成为FDM复合材料零件设计的必要部分。提出了一种计算方法，该方法考虑到FDM挤出喷嘴中的会聚区，挤出物溶胀引起的流体膨胀以及喷嘴形状对挤出聚合物中纤维取向的影响，来确定喷嘴流域中的纤维取向。聚合物熔体在蠕变流中被建模为牛顿流体，并且包括挤出物膨胀膨胀。纤维取向是使用Advani-Tucker（1987）取向张量和Montgomery-Smith等人的“快速精确闭合”来计算的。等（2009年）假设Folgar-rnTucker（1984年）各向同性旋转扩散模型用于纤维-纤维相互作用。结果表明，在喷嘴段之前的剪切流如所期望的那样在流的方向上引起高度对准。该对准状态在喷嘴会聚区域内进一步增加。模头膨胀区域中的膨胀流导致沿流向的纤维排列明显减少，而横向于流向的纤维排列增加。

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  • 会议地点 East Lansing MI(US)
  • 作者

    B. HELLER; D. E. SMITH; D. A. JACK;

  • 作者单位

    Baylor University, Department of Mechanical Engineering, 1311 South 5th Street, Waco, TX,76706, U.S.A.Author to whom correspondence should be addressed: Blake_Heller@baylor.edu;

    Baylor University, Department of Mechanical Engineering, 1311 South 5th Street, Waco, TX,76706, U.S.A.;

    Baylor University, Department of Mechanical Engineering, 1311 South 5th Street, Waco, TX,76706, U.S.A.;

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